Method of making boiling cap plates for fractionating columns



Jan. 3, 1939. J. 1.. ALLEN 2,142,598

METHOD OF MAKING BOILING CAP PLATES FOR FRACTIONATING COLUMNS Original Filq Dec. 18, 1936 Iuve zza- Johh/Lxflizen, 77 M/BJMM it 4 y y (Hi '23s Patented Jan. 3, 1939 PATENT OFFICE METHOD OF MAKING BOILING CAP PLATES FOR FRACTIONATING COLUMNS John L. Allen, Dorchester, Mass, assignor to E. B. Badger & Sons Company, Boston, Mass, a corporation of Massachusetts Original application December 18, 1936, Serial No. 116,512. Divided and this application May 18, 1937, Serial No. 143,304

1 Claim.

This invention relates to the manufacture of boiling cap plates for fractionating columns and has for its object the construction of such a plate by simple methods which render it effective for 6 its designed purpose.

This application is a division of my-prior copending application, Serial No. 116,512, filed December 18, 1936.

Boiling cap plates, which form horizontal liquid 10 carrying sub-divisions for the successive chambers of a fractionating column, are provided each with a plurality of chimneys or short standpipes distributed in closely spaced relation over the entire area of the plate. These serve as passages 1 for the vapor from one chamber to the next upper chamber. A covering hood or cap about but spaced from the mouth of the chimney and presenting a vapor passage or passages below the liquid level compels the vapor emerging from the 20 chimney to pass down and thence to bubble up through the liquid before escaping to the next adjacent chamber above. The liquid to be fractionated is supplied to the uppermost chamber of the column and overflows into succeeding cham- 25 bers below through passages in each plate protected by a Weir which maintains a fixed liquid level over the entire plate.

For the designed efiective operation of a fractionating column, the chimneys at their points of attachment to the plate present a strictly liquidtight joint. A critical condition is the depth of the liquid through which the vapor passes, first down inside of and then up outside of the hood. This should be, as nearly as possible, the same for 35 each boiling cap over the entire area of the plate.

This depth is fixed by the distance the vapor passages in the hood are submerged below the liquid level. The maintenance of the same vapor pressure within all the boiling caps on each plate is 40 another important condition. This is'adversely affected by displacement of the tops of the chimneys with relation to the walls of the hood in different boiling caps on the same plate.

The common methodof constructing the plate,

45 with its assembled boiling caps, is first to punch out a multiplicity of openings in the plate designed to carry thechimneys, and then attach the chimneys thereto, after which the hoods are placed in position, either by being attached directly to the plate or by suspension on a suitable support above the chimneys. Both the punching operation and the attachment of the chimneys to the plate tend to set up buckling stresses in the plate which more or less distort it and throw it out of a true plane, so that when assembled with its boiling caps either the liquid depth through which the vapor passes or the vapor pressure within the hood varies with different boiling caps on the same plate.

One effective method of securing chimneys to the plate to provide the required liquid-tight joint may be had by providing a shoulder or flange on the chimney which rests on the mar-' ginal edges of the aperture against the upper side of the plate when the chimney is loosely installed therein, and providing furthermore a. short skirt on the chimney protruding below the plate. This skirt may then be rolled or crimped over against the under marginal edges of the plate aperture to form a flange and the plate edges squeezed under heavy pressure between the flange thus provided and the chimney shoulder.

' This crimping and squeezing action, however, in particular serves to set up stresses in the metal of the plate in and adjacent the area pressed between the fianges on each chimney, which stresses tend to distort and buckle the plate, throwing it out of a true plane. This effect becomes cumulative with the attachment of successive chimneys.

I have found that, by forming corrugations or indentations in portions of the metal of the plate lying between successive chimneys on the plate, buckling strains set up in the boiling cap plate in the course of its construction may be neutralized and the otherwise buckled plate, which would interfere with maintaining the desired conditions referred to when the chimneys are assembled thereon, may be caused to assume such a flat condition that the relationship of each chimney to its hood and of each hood to the liquid level remains Fig. 2 is a plan view of the same on a somewhat smaller scale;

Fig. 3 is a sectional elevation of the chimney before installation on the plate;

Fig. 4 is a sectional elevation of the annular collar employed to hold the hood in place, shown before its installation on the plate;

Fig. 5 is a plan view of a portion of a boiling cap plate showing the manner in which the boiling caps are distributed thereover; and

Fig. 6 is a sectional elevation, similar to Fig. 1, but showing, on a smaller scale, a boiling cap where the hood is suspended above the chimney.

Referring to the drawing and to the illustrative embodiment of the invention shown in Figs. 1 to 5 inclusive, the metallic boiling cap plate II, which is usually circular in formation, has formed in it a multiplicity of press-punched, closely-adjacent apertures distributed over its entire area, one for each chimney to be, installed. Each chimney I3 is formed from a metallic tubular member (Fig. 3) of an outside diameter fitting the aperture in the plate and having a shoulder l5 formed near its lower end in any suitable manner, as by folding out its walls thereat. Beyond the shoulder is a short skirt or extension IT.

The chimney in this form is placed on the upper side of the plate H, with its skirt Il protruding through the aperture (as shown in dotted lines in Fig. 1) and the shoulder l5 restingon the top of an annular sheet metal plate l5, which latter has an inside diameter the same as that of the plate aperture and is provided with an upsanding peripheral rim 2i (Fig. 4 and dotted lines in Fig. 1).

The plate is placed in a press having dies adapted to bend the protruding skirt 11 from the dotted line to the full line position shown in Fig. 1 and over against the lower marginal walls of the plate aperture. As each chimney is installed on the plate H, heavy pressure is appli'ed, causing the dies to nip and squeeze such walls between the bent over skirt and the portion of the annular plate l9 abutting against the shoulder l5.

After the attachment of the chimneys as described, the hoods are fastened in place. Each hood comprises a dome-like top 23 resting on a flanged foot 25 and having sides which are pro vided with a series of slot-like bubbling openings 21 immediately above the foot but terminating well below the level of the chimney top and below the level of the liquid maintained on the plate. The flanged foot on the hood 25 fits between the upright rim 2| and the plate l9, and when placed thereon the rim is bent over the flange 25, from the dotted line to the full line position shown in Fig. 1, and the aligned parts of the rim 2|, flange 25, plate 19 and plate ii are squeezed together under heavy pressure between suitable dies.

The liquid level designed to be maintained by the weir (not shown) is indicated by the dotted line X in Fig. 1, so that the vapor discharged from the chimney escapes, as indicated by arrows, through the bubbling openings 21 and thence to a chimney of the next upper compartment, passing downward through a depth of liquid represented by the spacing between the dotted lines X and Y, the latter indicating the level of the tops of the bubbling openings.

To offset the distortion of the plate ll hereto- 'fore referred to, there is formed one or more indentations in the walls of the plate between adjacent boiling caps, herein in the form of cormgations or grooves. Herein (Figs. 1 and 2) there is shown-surrounding each boiling cap a continucorrugations may be formed in the plate at any suitable stage in the construction of the boiling cap plate, but, in the case of the embodiment illustrated in Fig. 1, for simplicity in manufacture they may be readily formed in the plate simultaneously with the attachment of the hood, in the same press and by the same set of dies as are employed for the purpose of crimping the rim 2| of the annular plate over the flange 25 of the hood.

Such corrugations may be otherwise than continuous and otherwise than circular in form, but the shape illustrated and described lends itself to ease and simplicity in the process of manufacture. These corrugations may be pressed into the boiling cap plate to form a groove on either the upper or lower side of the plate.

In Fig. 5 there is shown a modified form of boiling cap. The chimney I3 is attached to the plate II in the same manner as heretofore described, the annular plate l9, however, being omitted. The hood or cap 3|, instead of being fastened -to thepiate l I, is herein suspended from above by suitable supports, such as the angle iron 33, which also acts to support a number of other hoods over the same plate and may be attached to the plate or to the walls of the column. In this case the bubbling slots are formed in the lower marginal rim of the hood, the flange 25 (Fig. 1) being omitted and the rim being spacedfrom the top of the boiling cap plate i l.

The corrugation 29 is formed in the plate H concentric with, and herein somewhat closer to,

the chimney l3 than in the case of the construction shown in Fig. 1. While the corrugations may be formed in the plate at any suitable stage in the manufacture of the plate, they may be readily formed simultaneously with the attachment of the chimney, in the same press and by the same set of dies as are employed for crimping the skirt I! of the chimney over the edges of the plate aperture.

While there is herein shown and described for the purposes of illustration one specific method and the steps thereof by which the boiling cap plate may be constructed, it is to be understood that such description is illustrative only and that wide variations may be made in the method of attaching the chimneys and the hoods and in the form andshapc of the corrugations, all without departing from the spirit of the invention.

I claim:

The method of making a boiling cap plate for a fractionating column, which consists in forming a series of apertures in the plate, compressively attaching a boiling cap part to the plate about each aperture, and simultaneously with such compressive attachment neutralizing the buckling strains induced through the fo" nation of the aperture and the compressive attachment of said cap part by pressing into the plate a corrugated formation concentric with the body of each of the said cap parts.

JOHN L. ALLEN 

